1. Field of the Invention
As described in my U.S. Pat. No. 3,911,938, issued Oct. 14, 1975, with the present day high cost of labor, automatic vehicle wash devices have gained significant popularity. However, since such mechanisms frequently require the use of high volumes of water in order to provide for adequate washing of the vehicle, many state and municipal governments have enacted pollution control legislation limiting the use of fresh water in such automatic car wash devices and closely restricting effluents released therefrom. Accordingly, a great demand has arisen for the treatment of water used in such car wash devices in order to reclaim such water for subsequent use and limit, if not entirely eliminate, the dumping thereof into municipal sewage systems.
2. Description of the Prior Art
Numerous efforts have been made to provide for efficient reclaim of water used in the washing of vehicles and such efforts have conventionally led to systems employing various types of filters. However, with the high cost of replacement filters it has been necessary to incorporate filters of the type that are capable of being periodically back washed in order to revitalize such filters for subsequent filtering. Conventionally, such back wash has been accomplished by the use of fresh water from the municipal water supply, thus unnecessarily consuming fresh water and significantly detracting from the performance of the system in conserving water. In my aforementioned U.S. Pat. No. 3,911,938, I disclose an arrangement for utilizing four identically sized filter tanks, three of which are utilized to back wash a single tank. However, equal capacity filter tanks may be connected together for forward flow through one to clean the water and reverse flow through the other to provide for cleaning of the filter itself, thus conserving cleaning time and minimizing down time required for such cleaning. Further, it has been found extremely advantageous to direct the back wash water through the sludge separator prior to return to the water sumps to thereby minimize contamination of the sumps and minimize the cleaning requirements thereof.